Means for preventing accumulation of static electricity upon belting.



PATENTED MAR. 20, 1906.

C. M. GREEN. MEANS FOR PREVENTING ACCUMULATION OF STATIC ELECTRICITY UPON 1 'BELTING.

APPLICATION rum) NIB. 5, 1903.

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w 6 9L n F I w I M Q Q Q C n NQE ['NVENTORZ Charles Mfireen, mp

- JPCL \A/iTNESSESI i s'rArns PATENT OFFICE.

' cHARmrs-M; GREEN, or L NN; M'AssAcHosm'rs, iissrenoa 'ro GENERAL 7 "ELECTRIC-COMPANY, A CORPORATION OF NEW Y RK.

I MEANSFOR PREVENTING ACCUMULATION F STATIC ELECTRICIIY'UPON BELTING.

To allwlmm it mag concern:

Be it known that I, CHARLES M. GREEN, a citizen of the United States, residing at Lynn, in the county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Means for Preventin Accumulation of Static Electricity Upon elting, of which the following is a specification. In the operation of belt-driven machinery the frictional engagement between a pulley and its belt when the latter is made out of leather, rubber, canvas, or other material which is a non-conductor,'or, rather, a poor conductor of electricity, is found to generate static electricit which is accumulated upon the surface of t e belt. Under some circumstances this charge may become large. In such cases it is dangerousfrom its liability to cause fire. It is also a t to dama eelectrical apparatus which may appen to e in proximity to the belt. In any event the accumulation is a source of inconvenience and annoyance to the attendant or others who may approach the belt because of the discharge which is apt to take place to their bodies.

I have discovered that if belts be treated in such manner as to make their Working surfaces fairly good conductors of electricity no charge will be accumulated on the belt in thosecases in which the pulleys are also made out of conducting material. When some or'all of the ulleys which engage the working surface 0 the belt are formed of non-conducting material, it is necessary in Order to avoid the liability of accumulating a charge upon the belt that the pulleys should also be treated in such manner as to make their working surface electrically conductive or that an electrical connection be made to ground from the belt. When some of the pulleys enga ing the working face of the belt are formed 0 conducting material, a connection to ground may be easily made from one of the conducting-pulleys; When all of the pulleys are formed of conducting material, such as iron, the making of the working surface of the belt conducting is alone sufficient to avoid all liability of accumulations of static electricity upon the belt or pulleys and no grounding is necessary.

One method which I have emplo ed to make the working face of the belt cond ilcting and which I have found to be satisfactory in practice has been to treat it with graphite.

, Specification of Letters Patent. 7

- Application filed February 6, 1903'. I Serial No. 142,014.

Patented. March. 20, 1906.

The graphite may be mixed with the beltgrease ordinarily employed to keep the belt in a satisfacto condition. I have found that when grap to is so applied the slip is not excessive, as might be expected.

Other methods may be em loyed to make the working surface of the beii; conducting as, for instance, by inserting a pluralit of metallic contacts in it and connecting t ese contacts by metallic conductors.

In the accompanying drawings, 'Fi re 1 is an elevation illustrating one form o r ny invention. Fig. 2 is a lan view of a belt, illustrating a modified orm of my invention. Fig.3 is a sectional view taken on the line 3 3 .of Fig. 2, and Fig. 4 a plan view showing another form of m invention.

Referring to ig. 1, 1 represents a motor secured to a ceiling 2. The motor carries a pulley 3, and a belt 4, passing over the pulley 3, drives the pulley 5 on the shaft 6. Graphite mixed with belt-grease is applied to the working surface 7 of the belt 4. This causes the working surface ofthe belt to become a conductor. The pulleys 3 and 5, if made out of non-conducting material, such as aper or wood, will also become conductors om the graphite applied to the belt. Under these circumstances no static charge. will be accu mulated either on the working faces of the belt or pulleys.

In the construction shown in Fig. 2 looped pieces of metallic wire 8 pass through the elt' at intervals, the clenched ends 9 being on the Working side of the belt. The other ends of these pieces are connected by wires 10 on the outer surface of the belt. With this construction the char e which will accumulate upon the surface 0 the belt is determined by the farthest distance which it will have to creep to reach the ends 9 of the wires 8. This can be made as small as desired by increasing the number of contactpoints. In the construction shown in Fig. 4 longitudinal seams 11 of wire are formed in the belt. The various seams may be connected at one or morepoints by cross-wires 12, thou h thisis not important.

wt in connection with belting, it is not limited thereto, but may be applied wherever two surfaces one of which 1s normally non-conducting are in frictional engagement with one another.

le my invention is particularly useful What I claim as new, and desire to secure I leys, a leather belt connecting the same, and by Letters Patent of the United States, ismeans for preventing the accumulation of 1. A belt, and means for --rendering its i static electricity upon said belt comprising a 15 working surface conductive of electricity, coating of graphite applied to the working 5 comprising a layer of graphite applied to said surface of said belt.

working surface. In Witness whereof I have hereunto set my 2. In combination, a bplt, a plplley lengaghand this 3d'day of February, 1903. in said belt, and means or ma in t e surfazes of said pulley and said belt co nductive CHARLES GREEN 10 of electricity in order to prevent the accumu- Witnesses:

. lation of static electricity upon said surfaces. DUGALD McK. McKILLoP,

3. In combination, a pair of metallic p'ul- JOHN J. WALKER. 

